// the file descriptor dirfd. If name is anything but a directory (this
// includes a symlink to one), it should return an error. Other than that this
// should act like openFileNolog.
//
// This acts like openFileNolog rather than OpenFile because
// we are going to (try to) remove the file.
// The contents of this file are not relevant for test caching.
func openDirAt(dirfd int, name string) (*File, error) {

	// adds /name to the beginning of dir.
	dir = ""
	for parent := ".."; ; parent = "../" + parent {
		if len(parent) >= 1024 { // Sanity check
			return "", syscall.ENAMETOOLONG
		}
		fd, err := openFileNolog(parent, O_RDONLY, 0)
		if err != nil {
			return "", err
		}

		for {
			names, err := fd.Readdirnames(100)
			if err != nil {
				fd.Close()
				return "", err
			}
			for _, name := range names {